Emerging adulthood is a discrete developmental period, spanning the ages of 18-25. This period is distinct demographically, psychologically, and subjectively from other developmental periods. Many individual-level changes experienced during emerging adulthood can be attributed to social role transitions in educational, occupational, social, and family structure domains. Social role changes are in turn associated with changes in environments. These major changes in social roles and environments are thought to influence the trajectories of substance use. Emerging adulthood is a period of tobacco use experimentation and transition to regular use and dependence. College students make up a large proportion of emerging adults and have high rates of tobacco use, especially novel products, such as hookahs and cigarillos. Moreover, college students are targeted by the tobacco industry, making them a particularly vulnerable group. Upon graduation, these emerging adults experience significant social role and environmental changes, which may be associated with changes in tobacco use. However, few studies have evaluated the longitudinal trajectories of use of these products during the post-college period, and those few were focused exclusively on cigarettes. As a result, significant knowledge gaps exist in our understanding of (a) longitudinal patterns of tobacco use - given the diversity of products available, which hampers the development of effective interventions; and (b) how social role transitions and environmental context impact tobacco use during this important developmental period. The proposed study aims to fill these gaps. This renewal application builds on our previous research on tobacco use trajectories among college students by proposing to continue to follow a large cohort of 3,146 participants recruited from 11 colleges in North Carolina and Virginia. Using a prospective longitudinal design, participants were recruited during their first semester (fall 2010, and followed through fall 2014, one semester post-college (for most). By wave 6 (fall senior year), 75% had used at least one tobacco product in their lifetime, and 36% were current users, with 18% currently using more than one product. Given the changing market and emerging need for new public health approaches, this work remains critical to continue. In this application, we propose to follow the cohort for 4 additional years, surveying them every 6 months, and ultimately spanning a total of 8 years. Thus, the aims of the proposed study are to: (1) prospectively assess trajectories of tobacco use, including experimentation, progression to regular use, product switching, poly-tobacco use, and cessation during the post-college period; and (2) assess how prior tobacco use, social role transitions, and changes in environmental contexts relate to tobacco use patterns during the post-college period. The multidisciplinary team, led by a highly qualified Early Stage Investigator, has unique skills and expertise. The ultimate goal of this research is to identify those most at risk for nicotine dependence, by pinpointing social role transitions and environments associated with increased tobacco use, allowing for the development of effective interventions.